It is well known to design projectiles having a smaller caliber encased in a larger caliber sabot. The projectile must fit tightly within the barrel to maximize the efficiency of the propellant charge. Gaps about the projectile allow for the propellant force to escape so the sabot must make up the space between the barrel and the small caliber projectile. The sabot then transfers the propellant driving force to the smaller projectile. The sabot typically breaks into pieces after leaving the muzzle of the gun. In this way a larger caliber gun can have increased performance and the ability to perform multiple missions.
Previous approaches to launching smaller diameter munitions from a gun with a larger bore include utilizing full size sabots to build up the diameter of the projectile to the larger gun bore diameter. A sabot is typically formed from 2 or more petals. The petals surround the smaller projectile. The petals are heavy, and fly a long, unpredictable distance from the bore of the gun, creating a large Surface Danger Zone (SDZ) in front of the gun. An impact by a sabot petal may cause serious injury or death.
Split sabots are another alternate approach to placing a smaller diameter projectile into a larger diameter gun bore. The split sabots are generally smaller and lighter than the full length sabots. However, as with the full length sabots, the split sabots have petals that may injure personnel upon exiting the bore. In addition, the split sabots may damage the gun or the projectile if they split too early.
As the current methods create a danger zone as the petals detach, a new approach is needed that improves the safety and efficiency for smaller than bore projectiles.